Abstracts

This study examined the potential effects of epilepsy surgery on memory in children and adolescents. It is novel in that it includes a nonsurgical comparison group, tracks change over time, and includes qualitative and quantitative methods. The qualitative component illuminates the experiences of the participants and how they make sense of their memory difficulties. While it may be hoped that an improvement in seizure status coupled with on-going maturation would result in benefit to memory, work with adults suggests that outcome is not a static process, and decline in verbal memory over time after left temporal lobectomy has been observed. This possibility has not been investigated with the pediatric population for whom there is little information on long-term cognitive change after surgery. Memory was investigated in 27 participants in a longitudinal study before (T1), and at one (T2) and two to four years (T3) after epilepsy surgery. A comparison group with intractable epilepsy (n=15) matched in age, sex, age of seizure onset and IQ, was studied at the same time points. Methods included qualitative interviews to probe the participants[rsquo] perceptions of their memory over time and administration of standardized tests of story recall and face recognition. At T1, 20 (74%) youth in the surgery group and 9 (60%) in the comparison group reported memory problems. The following changes were reported by the surgical group: at T2, 9 improved and 4 declined; from T2 to T3, 5 improved and 3 declined. In the comparison group, 0 improved and 6 declined at T2; 2 improved and 1 declined by T3. Narrative themes were similar in both groups, with persistent deficits in retention of information and academic performance reported most frequently. On-going problems included difficulties with word-finding and memory for personal semantic information. Transient memory problems were worsened by seizures, medication and fatigue, which in some instances affected memory by reduced concentration, attention and understanding. Persistent and transient memory deficits caused fragmented learning and poorer academic performance. There was no significant change over time in either group on the standardized measures. Site and laterality of excision, age at surgery and seizure outcome were not predictive of change in the surgical group. Up to 4 years after surgery, little benefit with respect to memory was documented. Of importance, there was also no evidence of decline in the majority of participants. The narratives revealed a complex of factors that impacted on memory. Although objective tests did not show change, these tasks emphasize episodic memory. The narratives indicated that semantic memory may be affected by surgery, suggesting that the effects of surgery on this type of memory warrant further investigation. (Supported by The Ontario Mental Health Foundation)